Containers having removable caps are used ubiquitously and have been for many years. In many instances, containers are provided with means to indicate that the cap has been removed since the container was originally filled. Such tamper-indication provides the intending user with instant evidence of the freshness or safety of the goods within. This may be vitally important in containers which hold food or medicine. Recent occurrences of product tampering wherein foods and medicines have been illegally altered and poisoned have made the inclusion of tamper-indication means on many food and medicine containers a required feature.
Such tamper-indicators have been provided in many forms, from the paper seals permanently taped over liquor bottles to the elaborate packaging of many over-the-counter medicines. Caps for bottles which contain liquids such as soda, spring water, milk, and such, are often provided with frangible elements as integral portions of the cap which must be torn or separated from the cap before the cap can be removed. These frangible elements usually include means to positively secure the cap to the bottle so that the cap cannot be removed while the frangible element is still attached. Once removed, the cap can be snapped or screwed off of the bottle, but potential later users can instantly recognize that the frangible element is no longer integral with the cap, or no longer present at all, and can thereby ascertain the risk of using or consuming the remaining contents.
Such frangible tamper indicators have been offered countless times throughout the prior art. Two types of such indicators are most common in the recent prior art; those having a screw-off cap with a continuous annular frangible ring that remains on the bottle after opening, and those having a snap-off or screw-off cap and a non-continuous removable frangible ring including a pull-tab to initiate tearing and removal of the ring from the cap along a groove or perforation.
Those of the former type with the continuous frangible ring are generally provided in a molded plastic or stamped sheet-metal cap. The frangible ring is adapted to engage the bottle neck and prevent axial movement of the cap from the bottle. Simultaneous removal of the cap from the bottle and the ring is accomplished by twisting the cap to unscrew it with enough force to separate the cap from the ring. Because the axial separating forces are distributed fully around the circumference of the perforation or groove, the forces must be quite high to cause separation. The engagement of the ring to the bottle must be secure enough to withstand those separating forces and maintain the ring on the bottle, or the tamper-indication will be overcome. The perforation or groove must be precisely sized to allow separation with practical ease while having enough strength to maintain the sealing engagement of the cap and bottle. Unfortunately, the fine balance between the various and variable components is difficult to maintain. Such caps are often too difficult for many users, such as the elderly, to twist-off. The pull-tab type ring has therefore become one of the most common types used in low-cost containers and containers often used by the elderly, such as in blow-molded plastic milk bottles.
Those tamper-indicators of the latter type with a pull-tab have become so popular in main part because the pull-tab provides an easy means to start the separation of the ring from the cap, requiring very little physical strength on the part of the user. The pull-tab provides significant advantage in allowing initiation of the tear at a localized section of the groove, then provides a convenient handle for pulling the ring away from the cap around the groove. Such tamper-indicators have been the subject of numerous patents, such as U.S. Pat. No. 5,190,178.
In U.S. Pat. No. 5,190,178, the disclosed threaded cap and neck configuration must be rotated for removal and re-application of the cap. The frangible tamper-indicator includes voids which are engaged by lugs in the neck collar to prevent such rotation. Because the voids and lugs must be aligned, and the threads must be aligned, prior to assembly at initial bottling, the singular pull-tab of the ting serves as an orientation feature which is used by an orientation machine to determine the cap's original rotational position and to then re-orient the cap into the desired rotational position for assembly. As is disclosed, the pull-tab must be a singular and significant enough discontinuation from the cap's round shape to allow its location by the orientation machine.
One noteworthy advantage of the continuous ring, however, is that it is tolerant of the direction from which the bottle is approached and the cap is removed by the user. The bottle can be taken in hand and the cap can be grasped and twisted regardless of the rotational position of the cap. Whereas, with the pull-tab type ring, the cap most be positioned or the bottle must be rotated so that the pull-tab is convenient for grasping. This is particularly evident in bottles having handles such as blow-molded plastic milk bottles. It is most comfortable and convenient that such bottles are held by the handle with the secondary hand, the left hand in most cases, and the pull-tab is grasped with the primary hand, the right hand in those cases. Depending on the rotational position of the pull tab on the bottle relative to the handle, the pull-tab may be inconvenient to grasp while holding the handle as such. The pull-tab may be convenient to right-handed users but not to left-handed users, or vice-versa. If the pull tab is positioned rotationally opposite the handle, it is inconvenient to all users. Rotation of the pull-tab to a desirable position on the bottle is difficult and inconvenient at best, and likely impossible. On a screw-off cap, it is impossible. The pull-tab position is determined by the relative rotational position of the cap and bottle at the bottling plant during loading of the bottle.
In order to position the pull-tab during bottling for convenient access by most users, an orientation machine may be employed to locate the pull-tab for orienting the cap as earlier mentioned, and to thereby position the pull-tab relative to the handle for easy access by right-handed persons. However, the expense and complication of employing such a machine in the bottling process is prohibitive, and the cap is still not easily accessed by left-handed users, who represent a significant portion of the using population. Also, the pull-tab must again be a singular and significant enough discontinuation from the cap's round shape to allow its location by the orientation machine, or else an additional such orientation feature must be provided.
The bottling and container industries today suffer from the lack of an easy-to-assemble, tamper-indicating cap which is equally convenient to both the left-handed and the right-handed user while being easy for that user to remove.